Help Requested for creating Volcanic Lair, please

[Falcos]

Hi all. I'm presently trying to design a volcanic lair for my campaign's BBEG.

For reference, the BBEG is a Great Wyrm Red Dragon who has been divinely cursed into a human body and unable to get back to Draconic form unless he breaks that god's curse.

His endgame here is to enact a ritual to break the curse that needs one of the player characters' presence (my players are unaware of this particular requirement).

I am attempting to design his lair, which is based in a place called "Watchman's Peak", which was once a city built around a holy site of the forge-god who cursed him. He has since taken residence in it.

My player party is level 18-20, and contains mostly casters. I feel like my current plans are nowhere near challenging enough for them, so I would like the playground's help stepping this up, please.

Without further ado:

The entirety of the Peak is locked in a series of abjurations that takes most teleportation spells and redirects them to closed off, completely sealed rooms filled with sulphurous, poisonous gases.

The mountain is divided into four different layers of caverns, each constructed to be as labyrinthine as possible, made of a carefully constructed blend of stone, ash, and volcanic glasses, to hinder any attempt to manipulate the stone flooring or pass through it with earth magic.

Outside the ground floor entrance to the Peak, there are several areas where the floor is underlaid by deep pits, with magically enhanced obsidian oozes hiding in the pits, ready to attack and attempt to devour any trespassers. These pits are not magically hidden, but are instead mundanely concealed beneath carefully disguised sheets of thin volcanic glass.

The ground floor is primarily a living space for a specific underling of the BBEG, who has used it as their base of operations while they try to use diplomacy, seduction, and mind control to sway various factions and powerful individuals to their cause. It is superficially made into a very lavish, lush, and nice place to live, currently inhabited by said mind-controlled and persuaded peoples, once movers and shakers in the world, now little more than puppets at the whim of this lieutenant. There are eight of them and they are designed as PC races with PC levels, of various classes.

While superficially a living space, however, the entire ground floor is riddled with points in the walls where a single piece of errant damage would unleash a gout of magma into the room, potentially killing anybody close enough.

The second floor is largely the remains of the dwarven settlement that once resided in Watchman’s Peak. It has largely fallen into disrepair, but contains sub-caverns that were once homes, dormitories, smithies, churches, town halls, markets, etc. It is the ruins of a once-mighty city, long abandoned by the original inhabitants, and now occupied by dragon worshippers. They are less individually powerful than the enemies on the floor below, but are more numerous.

While filled with less traps than the ground floor, the traps here are generally more magical in nature, rather than relying on the volcanic nature of the mountain for defense.

The third floor is nearly completely flooded with magma flows, and patrolled by red dragonspawn cryohydras, who will use their breath weapons on any intruders trying to swim through the molten rock, damaging them and solidifying the stone to suffocate them. The entire floor also has several teleportation traps spaced through the magma flows that will send them to the aforementioned sulphuric chambers.

The fourth and highest internal floor contains the red dragon BBEG’s lair, the prison in which they have imprisoned the NPC that the party is trying to rescue, and a ritual chamber, in which the BBEG will await the party. Also on this floor are a Great Wyrm of each of the five primary metallic variations, under layered Domination effects to make them slaves to the BBEG.


Any feedback/help welcome, please. I want to make this as glorious as I can for my party.

[Efrate]

Line every important room with lead. have it melted if need be between thin riverine/wall of force barriers.

Dispel traps with CL as high as you can muster at every floor entrance(quick resetting traps) and any place that looks "safe" for resting. If you can shut of e tramensional storage or space it would be grand as well.

[Biffoniacus_Furiou]

Here ya go!
https://forums.giantitp.com/showthread.php?322346-Volcanic-mountain-cavern-style-dungeon-as-red-dragon-lair#2
And an updated link for Obsidian Ooze (http://archive.wizards.com/default.asp?x=dnd/fw/20031123a), even.

[Falcos]

Very much appreciated!

I'm just concerned that my current plans are not high enough CR for the party, and don't really know a good way to step up the CR.

[Biffoniacus_Furiou]

Monsters can be given class levels, hit dice, size increases, ability score increases, etc. for increased challenge rating (https://www.d20srd.org/srd/improvingMonsters.htm#advancedMonsterChallengeRati ng). Some are far more economical than others. For example, a Hill Giant is 12 HD and CR 7, give it Cleric 12 as nonassociated levels and it's 24 HD and CR 13, whereas a Human Cleric 12 is 12 HD and CR 12. Anything with class levels automatically gets the elite array without increasing its CR. A monster that gains size as it gains HD gets CR increases for the size increases.

If you want to make the dragon stronger, give it five levels of Abjurant Champion in CM, which makes its caster level equal its BAB and allows it to cast up to 3rd level abjuration spells as though quickened. That's a +5 CR that also gives it the elite array.

Templates are another option, like my suggestion of a Half-Red-Dragon 12-Headed Cryohydra in the post I linked.

What opponents are you planning to throw at your party? What's the party makeup and level? Which opponents do you think won't be enough of a challenge?

[Falcos]

The party, as it currently stands:

A Wu Jen/Swordsage/JPM, who specializes in AoE fire damage
A Warlock/Hellfire Warlock/Wizard, who is a vitriolic blast spammer
A Beguiler/Shadowcaster/Noctumancer/Mystic Theurge, who is a dedicated counterspell/dispel specialist (It makes sense given the context of the campaign)
A straight-up Sorcerer who optimized her Charisma into the low stratosphere and is now a charm/dominate specialist
And the one non-caster of the group, a Crusader.

Enemies I have currently planned:

Obsidian oozes at the entrance to the cave, as you recommended to me in two threads, now. I plan to increase their HD, although I'm not sure by how much. I'm also not sure how much of a threat they'd be no matter how much I increase their CR.
Eight NPCs-built-as-PCs for the enemies on the first floor. I was planning to have them be a variety of different classes, but fought either individually or in pairs, and of equal level to the party. I'm unsure how much of a threat that will be, either.
On the second floor, I have plans for waves of dragon worshippers to be the opponents - clerics, dragonfire adepts, and any other suitably draconic-themed things I can think of, in waves of a dozen or so at a time. I'm unsure what a good level to put those enemies at is.
On the third floor, I planned to have the main challenge be the lava itself - but I do like the idea of having things in it, such as the cryohydras. I'm open to more such ideas.
On the final floor, there will be five out-of-the-box metallics who have been Dominated into being enemies, and then the BBEG himself, who I plan to give some levels in Abj. Champ. I made a thread already asking for advice on how to build him, and I think I gleaned some useful ideas from it.

The party currently are all either level eighteen or nineteen, and I aim for at least some of them to be twenty by the time they reach the BBEG. I'm really, really unsure how to DM for this level of power, though - I've never had the opportunity to play at this level of power before and this is the first time I've DM'd this high.

[Segev]

Replace the dominated great worms with necromantically-controlled ghost dragons (still great worms). If there’s time before the party gets here, add legends of the BBEG’s crimes in killing each one personally, and desecrating their lairs so their bones could not be laid to rest. Or even stealing them; in that case, have the skeleton dragons be the chaff-winnowing guardians for the lieutenant on the first floor, maybe even plated in the precious metals of their type and posed as decorative sculptures outside.

The reason for going with ghost dragons is that it can be harder to dispel the control if it’s related to use of rebuke/command, or anything you custom-make to be related to it. Also, the incorporeal ghost dragons can fight easily in narrow corridors and retreat into the walls and otherwise harass the party.

Litter the ground outside the volcano with shards of stones that come from eruptions. Maybe make the approach treacherous with the eruptions growing more frequent as the ritual draws near. The falling crystals can do some amount of appropriate damage to those without protection.

Let the smarty pants in the party, if they investigate, note that the shards are technically an alchemical acid, but have to be suspended in solution to be dangerous as long as you don’t lick them.

Of course, what you should not spell out for them is that this means the molten form is also an acid. They might go in prepared for fire, and even think to double down with cold in case of a switch-up (like your cryo-hydrae), but they might not be ready for the lava to do as much acid damage as it does fire damage.

Make the teleport trap rooms rigged with cone of cold traps that go off every few minutes, and the floor slick glass and ice. The arrival point is a pillar of stone flush with the floor, and magma boils just beneath the glass. If they move off the arrival point, the glass breaks and they fall in; the next time the cold trap fires off, the glass is re-solidified. After the exposed acidic lava refills the room with a fresh dose of the toxic gas.

Enchant the whole place with Guards and Wards, just to be annoying. Those who belong are unaffected by it.

Oh, and given his god-hatred, maybe give the BBEG Ur-Priest levels and a lot of Quells (from Libris Mortis). The Quells are there to do as much interference with divine casters as possible. Especially preventing turn/rebuke.

[Falcos]

While I am loathe to make the lava acidic due to the in-universe mythology surrounding the mountain (It's meant to be the place where the forge-god first created the world, and acid doesn't really seem to fit to that story in my mind), I really, really love the rest of your ideas. Ghost dragons also give me a really nice way to deal with one party's members propensity for being intangible to avoid hazards.

Is Guards and Wards selective in targets by default, or are you saying to have it metamagic'd or handwaved to not affect those who belong?

[Biffoniacus_Furiou]

Put a permanent Wall of Greater Dispel Magic in SC at each level transition, as well as the main entrance.


Entrance (Obsidian Oozes): The ceiling is high enough that it's well out of range of their darkvision. The floor is lit by lava etc. but the ceiling is dark. This is a guantlet room with wave after wave of enemies, you want them to expend roughly half their daily resources on this.

Throw in a miniboss/guardian: a Summoning Ooze (MM3) advanced to 21 HD, so it can Summon Monster IX every round, which makes it CR 12, then add 17 nonassociated levels of Cleric so it's CR 20 with the elite array. It has the Slime domain, its second domain is something unique and ooze-specific that allows it to telepathically link all the other oozes in the room, so they can all see what each other sees and they're all aware of each other's locations and statuses. Also make the summoning ooze's fast healing equal its racial HD because. Embedded in this ooze are various gear items, namely a standard metamagic rod of extend and a 6th level pearl of power which it uses to keep Superior Resistance and five Energy Immunities constantly on itself by using two 6th level spell slots per day. It's used Deeper Darkness heightened to 4th+ level all over the ceiling and on each obsidian ooze. It's taken Quicken Spell-Like Ability several times for its Summon Monster ability back when it was fewer HD and it had a lower spell level, which still work at its current level for some reason. Also Maximize Spell-Like ability if you want to summon five huge elementals with it a few times. It should mostly have medium and long range spells prepared that can disrupt opponents such as Wall of Stone, and use Implosion if opponents get close.

Edit: The Summoning Ooze should max out at Summon Monster VI at 15 HD/CR 9 as printed. Increasing it to 21 HD for Summon Monster IX despite that should be +1 CR per HD after 15, making it CR 15 before class levels as well as huge size (but no CR increases for size due to it not being a physical attacker). In this case only give it Cleric 11 to be CR 20, having 6th level Cleric spells should be plenty with it spamming Summon Monster IX every round. I should also mention that I intended for the summoning ooze to be on the ceiling.

Several Obsidian Oozes should be on the ceiling and will drop down onto opponents, especially to bring flying opponents to the ground. Treat them as a sharp improvised weapon/falling object, allow a Reflex save for half of 20d6 piercing/bludgeoning damage when one lands on someone, it takes 1d6 damage per 10 ft. fallen as well. Replace their improved grab with skewer, which on hit forces a Reflex save (DC 10 + damage dealt) or they're impaled on the obsidian shard. A skewered target can't move away from the ooze and is dragged along if the ooze moves if they're two or more sizes smaller than the ooze. A skewered target can take a full round action with both hands free to pull the shard out, but receives the same amount of damage they took from the initial hit when doing so. The ooze can automatically pull in and engulf a skewered target as a full round action on its next turn, they cannot escape until they remove all the shards skewering them even if they have Freedom of Movement. It will continue attacking and attempting to skewer an engulfed target every round. There are literally as many obsidian oozes as you need there to be, dropping from the ceiling or coming out of hidden tunnels under the floor as often as needed to make this challenging.

All of that combined could actually be extremely challenging for them, but at this level I'm sure they'll come up with something.


Second Floor (Eight class-leveled opponents): Build the opponents around a theme, especially if they're encountered in pairs. An anti-magic fire giant duo with AMF and grappling shenanigans (power attack bonuses grapple checks to damage your opponent without penalizing your grapple checks). A fear-effect-scaling (https://forums.giantitp.com/showthread.php?389244-Caedrus-Art-of-War-vol-1-Fear-Handbook) duo with levels in Dread Witch so immunity does nothing. A pair of Psychic Assassins (http://archive.wizards.com/default.asp?x=dnd/psm/20040723d) with Mind Cripple, TWF, and Gloves of the Balanced Hand, which deal 2 Int damage per sneak attack. Make them something that doesn't breathe such as warforged, with augmented touchsight (https://www.d20srd.org/srd/psionic/powers/touchsight.htm), and fill the room with heavy smoke so there's zero visibility and it's impossible to breathe. Spellthief 1/ Psion or Ardent 4/ Psychic Assassin 6/ Slayer 9 is an ideal build, keep in mind Psychic Assassin is 4/6 manifesting per the text, put a Wand of Wraithstrike in a wand chamber of a weapon on each of them which Spellthief allows them to activate, still a swift action per Rules Compendium. I don't know what to make the last pair, maybe some kind of ranged attackers that use the terrain to their advantage.


Third Floor (the floor is lava): Just a big lava pool, no apparent way to proceed unless they swim through a long winding tunnel to come out the other side. Sprinkle a few more Wall of Greater Dispel Magic throughout for good measure. If one half-dragon cryohydra wouldn't be enough of a challenge, put two in there and make a third show up in the second or third round if necessary. Or increase it to 20-headed with as many HD and a proportionate CR.


Final Floor (dragon mob): Be sure to use their spells to buff, and full attack and use breath weapons as often as possible. Blinding Breath in SC for one that qualifies, Dispelling Breath on one with caster levels (Steel (http://archive.wizards.com/default.asp?x=dnd/mm/20040328a)? Loredrake?) and Entangling Exhalation in RotD on one that's low damage (d4s) are all useful.

[Segev]

While I am loathe to make the lava acidic due to the in-universe mythology surrounding the mountain (It's meant to be the place where the forge-god first created the world, and acid doesn't really seem to fit to that story in my mind), I really, really love the rest of your ideas. Ghost dragons also give me a really nice way to deal with one party's members propensity for being intangible to avoid hazards.

Is Guards and Wards selective in targets by default, or are you saying to have it metamagic'd or handwaved to not affect those who belong?

Looking at the spell, guards and wards (https://www.d20srd.org/srd/spells/guardsAndWards.htm) seems to be designed to be put up when you're expecting an invasion of your turf within the next 30 minutes. It looks like well-trained guardians could lurk in rooms and attack, but wouldn't want to wander the halls.

So it would have to be a custom effect to let denizens ignore its effects. Perhaps they each have a tattoo or magic item that turns off the effects in their presence, but also lets the BBEG or one or more of his minions track and spy on them. Maybe even cast spells directly on them, which is how the mind-controlled folks in the first floor are so thoroughly mind-controlled.

[Bucky]

I'm unsure what a good level to put those enemies at is.

For a CR 18 encounter with 12 enemies, the target level is about 11. Or 4 12s and 8 10s for exactly CR 18.

Add one level per enemy for CR19. But if you send a lot of waves without much time to recover, they should individually be slightly under-CR.

[dantiesilva]

From what I understand the dragon is here because it was cursed meaning said god would have set in place a guardian to make sure no one could set it free easily. There is a 8th or 9th level spell that summons a greater elemental to said place if the area is disturbed (a quick search turned up summon elemental monolith which could call a CR 17 Fire Monolith to fight your pcs while in the lava before they can get through the final seal to the BBEG. A failsafe the god put in place to try and stop anyone from setting said dragon free? This would be the gods failsafe and thus not influenced by the BBEG goons who have learned to stay clear of the area or awaken the guardian. A player who speaks Ingan could thus try speaking with it for a good RP moment or they could simply try and fight it.